Electric drive machines and equipments such as hybrid electric vehicles (HEVs), electric vehicles (EVs), electric motorcycles, aircraft, and marine vessels include various output apparatuses such as motors, electric lights and indicators. Accordingly, an electric storage apparatus for supplying electric power to the output apparatuses is mounted on each electric drive machine and equipment.
The electric storage apparatus includes at least one electric storage device and an external housing for housing the at least one electric storage device. As a result, the electric storage apparatus secures electrical insulating properties by means of the external housing, while supplying the electric power corresponding to the number of electric storage devices to the output apparatuses.
There is known an electric storage apparatus that includes a first external housing for housing an electric storage device and a second external housing for housing the first external housing (see, for example, Patent Literature 1). The first external housing is made smaller than the second external housing so as to be housed in the second external housing. Further, the second external housing includes an opening portion for inserting the first external housing.
The first external housing and the second external housing are kept at a given positional relationship, and form a double partition wall around the electric storage device. Accordingly, the electric storage apparatus of this type is excellent in durability (resistance to vibration), and the electric storage device can be reliably protected under a vibrational environment.
Meanwhile, in the electric storage apparatus of this type, because the first external housing is made smaller than the second external housing as described above, a gap exists between the first external housing and the second external housing in the state where the first external housing is housed in the second external housing. Accordingly, looseness or play of the first external housing may occur inside the second external housing. Consequently, unwanted vibrations may be applied to the electric storage device and the like included in the electric storage apparatus.